Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various devices or components, such as control surfaces. Many different types of actuator configurations presently exist. One particular type of actuator is a linear electromechanical actuator (EMA). A typical linear EMA includes a power drive unit, an actuator shaft, and an actuation member. The power drive unit, such as a motor, is configured to supply a drive torque to the actuator shaft, via a drive shaft and, in many instances, suitable gearing. The actuator shaft, upon receipt of the drive torque, rotates, which in turn causes the actuation member to translate.
In many instances, the position of the device or component being moved by a linear EMA is sensed using a position sensor coupled to the EMA. The position sensor is typically implemented using a resolver, an RVDT (rotary variable differential transformer), or an LVDT (linear variable differential transformer). For system accuracy reasons, the position sensor is typically connected, during production, to one end of the actuator drive shaft. The position sensor “zero” (or reference) position setting is then set. Unfortunately, user handling of the post-production EMA can result in the “zero” position setting being lost. This in turn can lead to the need to implement undesirable post-installation rigging to ensure that the position sensor does not show an incorrect position due to actuator shaft-to-position sensor error.
Hence, there is need for an EMA that will not readily lose its “zero” position setting during post-production handling, shipping, and installation. The present invention addresses at least this need.